Superconducting fluctuation corrections to ultrasound attenuation in layered superconductors

TL;DR

This paper analyzes how superconducting fluctuations influence ultrasound attenuation and velocity in layered superconductors above the critical temperature, highlighting finite corrections and experimental detectability.

Contribution

It provides a detailed theoretical calculation of fluctuation corrections to ultrasound properties in layered superconductors, considering material-specific effects and the hydrodynamic limit.

Findings

Fluctuation corrections remain finite as T approaches Tc.

Suppression of divergent contributions for longitudinal sound perpendicular to layers.

Potential for experimental detection of fluctuation effects in layered organic conductors.

Abstract

We consider the temperature dependence of the sound attenuation and sound velocity in layered impure metals due to superconducting fluctuations of the order parameter above the critical temperature. We obtain the dependence on material properties of these fluctuation corrections in the hydrodynamic limit, where the electron mean free path is much smaller than the wavelength of sound and where the electron collision rate is much larger than the sound frequency. For longitudinal sound propagating perpendicular to the layers, the open Fermi surface condition leads to a suppression of the divergent contributions to leading order, in contrast with the case of paraconductivity. The leading temperature dependent corrections, given by the Aslamazov-Larkin, Maki-Thompson and density of states terms, remain finite as T->Tc. Nevertheless, the sensitivity of new ultrasonic experiments on layered organic conductors should make these fluctuations effects measurable.